Water often carries dissolved minerals, including silica. Silica is the oxide of silicon, the second most abundant element in the Earth’s crust. When dissolved in drinking water, silica exists primarily as orthosilicic acid, a highly bioavailable form. This trace element is a natural part of the human diet. Research is exploring its potential benefits, particularly for structural tissues and its interaction with other ingested substances, focusing on the advantages of dietary intake rather than the dangers of inhaling crystalline silica dust.
Silica’s Role in Connective Tissue and Bone Health
Silica is involved in the biological processes that maintain the body’s structural framework. It is necessary for the formation and maturation of collagen, the main structural protein in tendons, ligaments, and skin. Silica activates enzymes involved in the hydroxylation of collagen, which stabilizes the protein’s triple helix structure. Insufficient silica can result in weaker collagen fibers, potentially affecting the elasticity of the skin and the resilience of joints.
Beyond soft tissues, silica plays a supportive role in bone mineralization and strength. It is present at the initial site of bone formation, where it appears to promote the deposition of calcium and other minerals into the bone matrix. While calcium provides the hardness, silica contributes to bone flexibility, which helps reduce the risk of fractures. Studies have shown an association between higher dietary silica intake and better bone mineral density, particularly in certain populations.
Silica assists in maintaining the proper balance between calcium and magnesium, which is important for overall bone integrity. It acts as a biochemical facilitator rather than being incorporated into the bone structure as a primary component. This function is also relevant for the health of blood vessel walls, where silica helps maintain flexibility by interacting with structural compounds like glycosaminoglycans.
The Interaction Between Silica and Aluminum
Research explores the capacity of waterborne silica to interact with aluminum within the body. Aluminum is a pervasive element found in many foods and the environment, and concerns exist about its potential accumulation in tissues, especially the brain. The soluble form of silica, orthosilicic acid, is theorized to act as a natural chelator against aluminum.
This beneficial action occurs in the digestive tract, where silicic acid can bind to aluminum ions. The resulting compound is a large, non-absorbable molecule called an aluminum silicate. This newly formed compound cannot be taken up by the body and is instead safely excreted through the feces.
This binding mechanism effectively reduces the overall bioavailability of ingested aluminum. While the simple monomeric form of silicic acid has a weak affinity for aluminum, its oligomeric form demonstrates a significantly higher binding capacity. Human studies have shown that consuming this oligomeric silica can reduce the uptake of aluminum from the gut by as much as 67%.
Determining Safe Consumption Levels
Silica is widely distributed in the diet, found naturally in grains, vegetables, and many water sources. The concentration of dissolved silica in natural waters varies greatly, typically ranging from 5 to 25 milligrams per liter, though some groundwater sources reach over 100 milligrams per liter. Bottled waters, particularly those from volcanic regions, can also contain elevated levels.
The average daily intake of silicon for adults is estimated to be between 20 and 50 milligrams. Because silica is common and the body efficiently processes it, the U.S. Food and Drug Administration (FDA) generally recognizes it as safe (GRAS) for use as a food additive. The body excretes excess absorbed silicon efficiently through the kidneys, meaning it does not typically accumulate to harmful levels.
There is currently no formal Recommended Daily Allowance (RDA) for silica because its status as an essential nutrient is still under investigation. Safety assessments have established a No Observed Adverse Effect Level (NOAEL) for dietary silica at very high concentrations, suggesting a wide margin of safety. The general consensus is that consuming water with naturally occurring silica poses no health risk and may offer benefits.